Missions Curriculum for Elementary School. There are nearly 4,000 languages worldwide with absolutely no portion of God’s Word and many of them reside in the 10/40 window. The Opening the 10/40 Window in the Classroom curriculum was developed for use with elementary-aged students. The curriculum is based on Bibleless people groups and consists of thirteen lessons per people group. The areas of study for each people group focus on the following four categories: geography, culture, language, and religion.